Supporting apparatus for vessels

ABSTRACT

Apparatus for supporting a vessel, such as a blast furnace having a shell, comprising a main frame that surrounds the shell and is connected to and at least partially supports the shell by members that are under longitudinal stresses that can fluctuate but do not undergo stress reversal during normal operations of the vessel. A compression ring or auxiliary frame member surrounds the vessel and is fixed to the frame to stabilize it. Stabilizing tie means, all preferably essentially in the same horizontal plane, are disposed around the periphery of the shell and are connected to the shell and the frames. The supporting apparatus for the vessel also includes diverging legs rigidly connected to the main frame; during construction the lower ends of these legs are supported off center from the centers of the legs to enable the lower ends of the legs to deflect outwardly by amounts corresponding to the amounts that they would deflect when loaded with the vessel.

United States Patent [72] Inventors Melvin J. Gr'eaves Cleveland; TageWerner, Rocky River, both of Ohio [21] Appl. No. 811,527 [22] Filed Mar.28, 1969 [45] Patented Dec. 28, 1971 [7 3] Assignee Arthur G. McKee &Company Cleveland, Ohio Continuation-impart of application Ser. No.778,883, Aug. 29, 1968, which is a division of application Ser. No.520,945, now Patent No. 3,431,691. This application Mar. 28, 1969, Ser.No. 81 1,527

[54] SUPPORTING APPARATUS FOR VESSELS 45 Claims, 13 Drawing Figs.

[52] US. Cl 266/25 [51] 1nt.Cl. C21b 7/00 [50] Field of Search 266/25,24, 3 i; 263/29 [56] References Cited UNITED STATES PATENTS 1,217,1852/1917 Johnson 266/25 FOREIGN PATENTS 10,297 5/1894 Great Britain 266/2535,454 3/1930 France 266/25 555,231 6/1923 France 266/25 624,475 7/1927France 266/25 Primary Examiner-Gerald A. Dost Attorney-Bosworth,Sessions, Herrstrom & Cain ABSTRACT: Apparatus for supporting a vessel,such as a blast furnace having a shell, comprising a main frame thatsurrounds the shell and is connected to and at least partially supportsthe shell by members that are under longitudinal stresses that canfluctuate but do not undergo stress reversal during normal operations ofthe vessel. A compression ring or auxiliary frame member surrounds thevessel and is fixed to the frame to stabilize it. Stabilizing tie means,all preferably essentially in the same horizontal plane, are disposedaround the periphery of the shell and are connected to the shell and theframes. The supporting apparatus for the vessel also includes diverginglegs rigidly connected to the main frame; during construction the lowerends of these legs are supported off center from the centers of the legsto enable the lower ends of the legs to deflect outwardly by amountscorresponding to the amounts that they would deflect when loaded withthe vessel.

PATENTEDUECZBIBYI 3,630,507

SHEET 1 UF 5 INVENTORS. MELVIN J. GREAVES 8:

BY TAGE WERNER NW4 Cam ATTORNEYS.

PATENTEU DEC28 I97! SHEET a nr 5 INVENTORS. MELVIN J GREAVES &

TAGE WERNER now-OWL, M cah,

ATTORNEYS.

PATENTEnnecaaxsn 3530,50

SHEETBUFS INVENTORS. MELVIN J. GREAVES & TAGE WERNER MM,8MM fiM/MWWLMATTORNEYS- PATENTED UEC28 197:

SHEET 4 UF 5 INVENTORS- MELVIN J. GREAVES 8- TAGE WERNER BY 8%,8mm4, H

ATTORNEYS PATENTEU HEII28 IQTI SHEETS 0F 5 INVENTORS- GREAVES & RNERMELVI TAGE Hmlhwi Cox/r1 ATTORNEYS SUPPORTING APPARATUS FOR VESSELSCROSS REFERENCES TO RELATED APPLICATIONS This application is acontinuation-in-part of copending Melvin J. Greaves and Tage Wernerapplication Ser. No. 778,883 filed Aug. 29, 1968, which is a division ofapplication Ser. No. 520,945, now U.S. Pat. 3,431,691.

BACKGROUND OF THE INVENTION The present invention relates to improvedsupporting structures for upright or upstanding vessels, and moreparticularly to supporting structures for vessels capable of appreciableexpansion and contraction during its operation, such as blast furnaces.

In the United States, blast furnace structures heretofore conventionallyused generally have included a massive foundation set into the earth;the lower portion of the furnace including the hearth and bosh has beensupported by this foundation. The upper portion of the furnace,including the shaft and furnace top including the bells, distributor andupper portions of the downcomer, has been supported by a mantle that, inturn, has been supported on the foundation by numerous columnssurrounding the lower portion of the furnace in close proximity to eachother and to the lower portion of the furnace.

Such furnace structures have certain advantages in that the upper partof the furnace including the shaft and top supported by the mantle havebeen free toexpand thermally as a unit on heating of the furnace. Thedowncomer attached to the furnace top also becomes heated duringoperation of the furnace, so it also expands and contracts with theportion of the furnace above the mantle, thus minimizing difficultiesthat might otherwise arise from thermal expansion.

However, in such furnace structures there have been substantialdifficulties arising from the differences in the thermal expansions ofthe supporting columns and the lower portion of the furnace below themantle. The mantle-supporting columns themselves are not subjected tosufficient heat to cause them to expand appreciably, but the lowerortion of the furnace is subjected to high-temperature heat; therefore,the lower portion of the furnace tends to expand substantially onheating of the furnace until it bears substantially all of the weight ofthe furnace above the mantle and the apparatus supported by such portionof the furnace. On cooling, the lower portion of the furnace contractsand the entire load again is transferred to the columns. It, therefore,has necessarily been the practice to make the columns strong enough tosupport the upper portion of the furnace and apparatus supportedthereby, and also to make the lower portion of the furnace strong enoughto support the upper furnace portion and such apparatus; this hasinvolved substantial added costs. Furthermore, the lining of the furnacein the vicinity of the mantle has been susceptible to excessivedeterioration because of localized expansion and contraction arisingfrom transfer of the load from the columns to the lower portion of thefurnace and vice versa. The expansion joint often provided at thislocation to minimize this problem has, itself, been a source of trouble.

In conventional European blast furnace structures, the lower portion ofthe furnace including the hearth and bosh, and the upper portion of thefurnace including the shaft but not the furnace top, are supported froma massive foundation set into the earth. The furnace top, including theload equipment and downcomers, is supported from this foundation by longposts or columns. This design tends to overcome the above-describeddisadvantage of American-type structures, but introduces new problems.The bosh jacket is a structural element that supports the shaft of thefurnace; consequently, a hot spot in the bosh can impair the support forthe shaft; furthermore, the necessity for maintaining the bosh jacket asa structural supporting member increases the difficulties of reliningthe bosh. This design also makes it difficult to maintain a satisfactorytight joint between the furnace top and the portion of the furnace belowthe top. Since such portion tends to expand on heating, whereas thecolumns supporting the top do not expand appreciably if at all, thisproblem is accentuated when high top pressures are used according tomodern practice.

'Other problems arise because the downcomer, supported from the columns,expands due to heat while the columns themselves do not expand, andbecause portion of the chargedistributing apparatus is usually supportedby the furnace top and moves as the furnace expands, and a portion issupported from the posts and does not move from thermal expansion,consequently, jamming of distributor parts or gas leakage at thedistributor may occur.

As a result of dimensional changes in furnace parts during operation, asdue to expansion and contraction of the furnace shell from changingtemperatures or pressures, the supporting members in conventional blastfurnaces can be subjected to diverse and varying forces. Such forces cancause frequent stress reversals in furnace supporting members. Forexample, a member may be in tension at one stage of the operation of ablast furnace but put into compression as an adjacent furnace partchanges dimension due to a change in heat and/or pressure. Suchrepeating reversals from tension stress through zero stress tocompression stress followed by succeeding reversals through zero stressback to tension stress can promote fatigue failure in the supportmember. As is well know, a member can fail due to fatigue long before itmight otherwise fail due to stress-induced causes.

Furthermore, in conventional American furnace structures, as well as inmost European structures, the columns or posts that support the upperportions of the furnaces are so closely spaced in relation to the lowerportions of the furnaces, as well as to each other, that they impairaccess to the lower portions of the furnaces for operations such astapping, closing the tap holes and removing slag or spilled metal. Theyparticularly impair access to these portions of the furnace by automaticmachinery for performing these functions. Moreover, since the legs areclosely disposed relative to the furnace, they can be damaged by moltenmetal in the event of breakouts. Furthermore, in both American andEuropean furnace struc tures, it is very difficult, time consuming andexpensive to line the furnace, particularly the bosh and lower inwallportions which most frequently require lining, primarily because of thedifficulties of access to the furnace caused by the closely spacedcolumns and by the construction of the bosh and hearth portions whichmust act as supports for the upper furnace portions.

SUMMARY OF THE INVENTION It is an object of the present invention toovercome as many of these problems and disadvantages as are desired.Another object is the provision of support means for an upright vessel,

such as a blast furnace, in which stress in a support member canfluctuate but never pass through zero stress. Such a member is alwaysmaintained either in tension or compression in accordance with thepresent invention. Failure due to fatigue in such member may beeliminated.

A further object is to provide an improved system of stabilizing memberswhich, in one form, embrace an upstanding vessel at substantially thesame elevation to steady it.

A further object is the provision of gussets to support and reinforce afurnace shell or the like having a refractory lining, by having thegussets extend on the interior of the shell into the refractory.

A further object is to provide a process and structure for prestressingsupport legs or columns for carrying an upright vessel and its attendantparts, so that the legs are deflected during construction when notsupporting the vessel and essentially undeflected while supporting thevessel.

DESCRIPTION OF THE DRAWINGS These and other objects of the inventionwill be apparent from the following description of the invention inconnection with the accompanying drawings in which:

FIG. 1 is a side elevation, partly in section, of a blast furnaceembodying the present support means, parts not necessary for thedisclosure being omitted for clearness;

FIG. 2 is a transverse section of FIG. 1 on the line 2-2 to an enlargedscale;

FIGS. 3 and 4 are partial sections generally along lines 3-3 and 4-4,respectively of FIG. 2, to a still larger scale;

FIG. 5 is a section on line 5-5 of FIG. 1 and to the same scale as FIG.2;

FIGS. 6, 7, 8 and 9 are detailed sections on lines 6-6, 7-7, 8-8 and 9-9respectively of FIG. 5;

FIG. 10 is a somewhat diagrammatic side elevation of the supporting legstructure, illustrating prestressing ofsuch structure before a load isapplied, the deflections of the legs being greatly exaggerated for thesake of clearness;

FIG. 11 is an enlarged, fragmentary vertical section of the bottom endofone ofthe legs of FIGS. 1 and 10;

FIG. 12 is a section along line 12-12 of FIG. 11 and to the same scale;and

FIG. 13 is a fragmentary view, partly in section along line 13-13 ofFlG.land to the same scale.

GENERAL ARRANGEMENT In the illustrated apparatus, a supporting structure9 supports a furnace 10.

The furnace 10 comprises a shaft 11, bosh 12, and hearth portion 13, allenclosed in a continuous steel shell 14 free of sharp bends and linedwith suitable refractory material. The hearth portion may be supportedby an underlying foundation 16 indicated in FIG. 1, set into the earth,or it may be wholly or substantially unsupported by being suspended, asdisclosed by the above-identified related applications. A conventionalbustle pipe 22 surrounds the bosh 12 and communicates with conventionaltuyeres 23 leading into the furnace. Conventional uptakes 24 areconnected to the top of the furnace, which may also house or connect toother conventional equipment, not shown, such as a burden distributor,bell hopper, bells, downcomer, etc.

The structure 9 comprises a generally horizontal main frame, generallyindicated at 25, and widely spaced legs 26 that are rigidly secured toframe and supported by base 27 set into the earth. There may also be aworking or cast house floor, not shown, at the lower end of the furnace.Frame 25 also rigidly carries an upper auxiliary structure comprisingupstanding posts 28 connected to frame 25 and supporting severalhorizontal-disposed working platforms 29 as well as superstructure 30and other equipment usually associated with the top ofa blast furnace.

FRAME STRUCTURE Main frame 25 surrounds and is spaced from the shaft 11above and adjacent a ring member 31 adjacent the lower portion of theshaft between the shaft and bosh in essentially the same verticalrelationship on the furnace as a mantle in a conventional blast furnace.The frame 25 is polygonal in plan and, as illustrated, preferablycomprises (FIGS. 1, 2, 3 and 5) four deep horizontal steel beams 32 thatare rigidly welded or bolted together at their ends to form a square inplan. Each beam 32, which may be about IO-feet deep on a large furnace,is an l-section girder having (FIG. 3) a wide vertical web 33, generallyhorizontal top and bottom flanges 34 and 35, and generally verticalreinforcing stiffeners 36. The top flange 34 of each beam carries twointernally laterally projecting portions 37 (FIG. 5) substantiallyequally spaced along the length of each beam 32 essentially at its thirdpoints. Beams 32 may be conventionally fabricated, as by welding fromsteel plates.

At each of several locations of essentially equal deflection on frame25, which are essentially at the third points of beams 32 in theillustrative embodiment to provide eight symmetrically spaced locations,there is a relatively large inwardly projecting plate connector member38 (FIGS. 1, 2, 3, 5) essentially vertically and radially disposed withrespect to the axis A of shaft 11, about which frame 25 is essentiallysymmetrical.

Each member 38 is welded at its upper edge to a projection 37, and atits outer edge to web 33, of a beam 32. The inner edge of each member 38slants downwardly and outwardly from shaft 11.

At the juncture of the shaft 11 and the bosh 12, supporting gussets 39in the form of upstanding thick steel plates extend between and arewelded to the top of ring member 31 and the outside of the shell 14 atthe lower portion of the shaft. Preferably the ring member 31 is fixedto the shell of the furnace at a location such that when the furnace isempty or filled, the center ofgravity of the furnace is below ahorizontal plane containing the center of gravity of frame 25.Stiffening gussets 40 and 41, essentially radial with respect to theshaft 11, also are welded to and extend from the outside ofthe shaftshell and the top of ring member 31. Lateral stiffeners 42 and 43 (FIGS.2, 3, 4) are fixed to gussets at their upper and outer edges. Thus,lateral stiffeners 42 are welded to the outside of the furnace shell andto the upper ends of each gusset 39 and its adjacent gusset 40, whilelateral stiffener 43 takes the form ofa strip welded to the outer edgesof all gussets and the ring member 31.

The outer edge of the ring member is polygonal in plan having straightedges that extend between the gussets 39 (FIG. 2 Gussets 39 thereforeextend radially from the furnace shell a greater distance than gussets40 and 41. These shapes and relationships of ring member 31 and thegussets provide desirable maximum strengths at the locations of gussets39 by which the shell is supported.

Connecting means, generally indicated at 44 (FIGS. 1, 2, 3 5) connectthe members 38 on frame 25 with the gussets 39 on the furnace shell 14.In the embodiment illustrated, means 44 comprises duplicate pairs ofelongated connecting members 45. Members 45 of each pair are shown asrelatively thick steel struts fixed to the opposite sides of members 38by bolts 46 extending through both members 45 and member 38, and to theopposite sides ofgussets 39 on the furnace shell by bolts 47 extendingthrough the lower portions of the members 45 and the gussets. Members 45extend diagonally downwardly and inwardly from frame 25 toward thefurnace shell and are located at the points of maximum deflection of theframe in essentially vertical planes that extend substantially radiallyto the furnace shaft 11, and essentially pass through and areessentially equiangularly spaced about vertical axis A of the furnace.

In such supporting structure, during changes in dimensions of the shell14 occuring during normal operations, such as expansion or contractionof the shell due to increases or decreases in temperature or internalpressure, the magnitude of the longitudinal stresses on the members 45fluctuate, but without reaching zero stress or undergoing reversal ofsuch longitudinal stress. By longitudinal stress" is meant the stress inthe members 45 between the locations where such members are attached tothe members 38 and 39. Preferably the members 45 are always in tension;they may be substantially rigid members as shown that are capable ofwithstanding substantial compressive stresses such as might occur inunusual circumstances such as explosions. As illustrated by FIG. 3,connector members 45 provide substantially the only direct connectionbetween frame 25 and ring member 31 on the furnace shell. Because oftheir inclination, they cause vertical and horizontal components oftension forces acting on member 31. The parts are so designed, moreover,that the forces to which ring member 31 is subjected by members 45during normal changes in dimensions of the shell may vary substantially,but they are always in one direction and do not reverse direction.

Additional means for resisting varying forces exerted on the furnaceshell at the juncture of the shaft and bosh, and on the ring member 31,due to variations in temperatures of pressures and weights of thefurnace due to changing loads include companion portions 39a, 40a and41a to gussets 39, 40 and 41, fixed to and radially extending from theinside of the furnace shell and fixed to the portion of ring member 31inside the shell. These inwardly projecting portions are embedded withinthe refractory lining 14 (FIGS. 2 and 3) which may also haveconventional coolers 48. Preferably portions 39a, 40a and 41a haveopenings 49 that remove sufficient area of metal to weaken theseprojections sufficiently so that during expansion and contraction of theshell these internally projecting portions can upset or change dimensiondue to compressive stresses without overstressing the outer gussets.Moreover, any upsetting of these internal projecting portions does notappreciably reduce their reinforcing effects.

COMPRESSION RING MEMBER A compression ring member generally indicated by51 and shown in the illustrated embodiment as octagonal with sides ofequal length and equal angles between the sides, is fixed as by weldingto the top flanges 34 of the beams 32 of the main frame 25. Member 51resists tilting of the beams 32 about their longitudinal generallyhorizontal axes, from forces arising from the weight of the furnace orfrom expansion of the furnace shell on heating or from increasedpressure. As the furnace shell increases in diameter for these reasonsthe lower ends of the connecting members 45 tend to move outwardly withthe lower portion of the shell of shaft portion 11. This can tend tocause the upper ends of the connectors 45 to move inwardly so thattheytend to cause the beams 32 to twist about their longitudinal axes sotheir upper flanges 34 tend to move closer to the furnace than theirlower flanges 35. However, any tendency of the beams 32 thus to twist ortilt is resisted by the ring member 51, which is thus subjected tocompressive forces. Since the ring member 51 is a symmetrical polygonwith straight sides at the junctures of which connectors 45 are located,member 51 is exceptionally efficient in resisting the forces to which itis subjected. A polygonal member is less expensive to make than acircular one, and is less subject to distortions due to heat or otherfactors to which it is subjected.

Member 51 may be fabricated from relatively thick steel plate welded tothe underlying beams 32 of frame 25. The internal corners of the polygondefined by member 51 are enlarged at 52 to provide increased materialand strength for connection to stabilizing ties to be described. Asshown in FIG. 5, these enlarged interior portions 52 overlie theinterior projecting portions 37 of the top flanges 34 of beams 32, whichthereby provide further support for member 51 and the stabilizing tiemeans 53 and 54. Ring member 51 thus acts as an auxiliary frame.

Stabilizing tie means 53 and 54, connected to shell 14 of the furnaceand compression ring member 51 around the shell, add lateral stabilityto the furnace in frame 25. Tie means 53 comprises a generallyhorizontally extending elongated fastening member 55 welded to thefurnace shell 14 and two tie bars 56, each connected at one end to anend of member 55 and the other end through a turnbuckle 57 to aconnector member 58 pivotally connected by pin 59 passing throughadjacent portion 52 of member 51 and portion 37 of beam 32. Each tie bar56 is formed of two spaced members 56a and 56b, (FIG. 6). Tie means 54is similar, comprising an elongated fastening member 61 welded in anessentially horizontal position to the furnace shell; this member hasits end portions forked at 62 to receive and be pivotally connected toone end of each of two tie bars 63. Each bar 63 passes between themembers 56a and 56b of a crossing tie bar 56 of the adjacent tie means53, and are connected through a turnbuckle 64 to a connector member 65that is pivotally connected by a pin 66 to adjacent portion 52 of member51 and portions 37 of a beam 32. Preferably the stabilizing tie means 53and 54 surround the furnace shaft 11 and are essentially at the sameelevation, as is made possible by the crossing of tie bars 56 and 63, sothat the lateral stabilizing forces acting between the frame 25 and theshell fall essentially in the same horizontal plane located above thecenter of gravity of the furnace and that of frame 25. Furthermore, eachtie means 53 and 54 and their tie bars and associated turnbuckles andconnector members extend essentially tangentially of the furnace shell,and the forces acting between the shell and frame 25 through the tiemeans are essentially tangential forces. The four tie means 53 shownessentially define a first square, while the other tie means 54 defineanother square intersecting the first square and is placed 45 angularly.Each square thus is a polygon of half the number of sides of thepolygons defined by the member 51 and the supporting gussets 38. Thelengths of the tie means can be adjusted as necessary by turnbuckles 57and 64, even while the tie means are in place.

LEG STRUCTURES According to another aspect of the present invention, theinclined legs 26 that carry the frame 25 of the supporting structure 9are, prior to loading of the supporting structure, first prestressed byhaving the lower end of each leg moved outwardly from its initialunstressed position in a direction and by an amount essentiallycorresponding to the direction and amount at the lower end of the legwould move outwardly from its unstressed position if the supportingstructure 9 of which the leg forms a part was subjected to a loadcorresponding to the furnace, so that the legs are deflected duringprestressing as exaggeratedly indicated by the full lines in FIG. 10.The lower ends of the legs are then secured in such position. Supportingstructure 9 is then loaded with the furnace so that the legs 26 assumepositions in which they are essentially undeflected, as shown in brokenlines in FIG. 10 and in full lines in FIG. I. The legs may thereafter befilled with poured concrete which is allowed to solidify; the concreteafter it has been hardened and cured stiffens the legs 26 and acts tomaintain them in their undeflected conditions under load, inwhichconditions they have their maximum strength.

According to the present invention, this outward movement of the lowerportions of the legs to achieve the desired prestressing is facilitatedby initially temporarily supporting each leg during construction, afterthe legs have been fixed rigidly to the frame 25, at suitable locationsoff center from the centerline parallel to the axis of the leg at lowerend thereof passing through this vertical center at the bottom of theleg at which the force resulting from the load would be concentrated;with a leg of circular or other symmetrical cross section about acenterline, as shown, such line is the centerline of the lower portionof the leg, and will for convenience be referred to as such below. Theleg is so supported off center by an amount and in a directioncalculated to cause the leg to move outwardly the desired distance inthe desired direction, to put the desired prestress in the leg. Thelower ends of the legs are then locked in such positions, and concreteor other supporting means is inserted under the bottom of the leg totake most or all of the load that is carried by the leg and representedby its proportion of the weight of the supporting structure 9 and thefurnace.

A shear and a bending moment is therefore temporarily applied to thelower portion of each leg during such prestressing construction, theshear being caused by the outward movement of the above described lowerportion of the leg, and the bending moment being caused by locating thetemporary support of the leg off the centerline of the leg. Such shearand bending moment are eliminated when the supporting structure 9 isloaded with the weight of the furnace.

More specifically, in the illustrated apparatus, the four legs 26 arerigidly connected to frame 25 at the four corners thereof as by weldingor bolting, the legs diverging equally in a downward radial directionfrom the vertical axis A of the furnace; the legs in a major portion oftheir lengths are of generally circular cross section and hollow, andquite limber until loaded and filled with concrete that hardens. FIG. 10shows diagrammatically in full lines the bowed dispositions of the legs26 when they are prestressed but not loaded, by having their lower endsdisplaced outwardly from the axis A of the furnace to the positions theyare calculated to assume under full load. Under load, the horizontalbeams 32 between the legs deflect and thus cause the rigidly attachedupper ends of the legs to have an outwardly directed bending movementwhich essentially removed the prestress deflection in the legs, so thatthere is no appreciable deflection remaining in the legs after loadingand the legs are straight and can develop their maximum strength, asshown by the broken lines in FIG. 10.

FIGS. 11 to 13 show preferable means according to the invention forsupporting the lower ends of the legs 26 off center and moving themoutwardly to prestress them as described. At the lower end of each legthere are internal reinforcing plates 67 and 68 that extend upwardlyfrom the bottom of the leg for a substantial distance. Plates 67 extendacross the interior of each leg at each side of axis X of the leg,preferably being welded into slots in the leg wall 69 (FIG. 12) whilecross plate 68 extends at right angles to plates 67, fitting and beingwelded in slots in plates 67 and in the leg wall.

The lower end of each leg 26 has a strong steel transverse flange 71fixed to the bottoms of the leg wall and the plates. The flange haselongated openings 72 for anchor bolts 73, two such openings beinglocated on the side of the flange nearest furnace axis A and six beinglocated on the opposite side of the flange toward which the lower end ofthe leg is moved in prestressing. A ball portion 74 of hardened metal,somewhat greater than a hemisphere, is fixed to a baseplate 75 welded onthe underside of flange 71 at a location such that axis Y passingthrough the center of portion 74 is parallel to axis X of the leg 26 anddisplaced by a predetermined distance 2 toward furnace axis A.

During erection, the ball portion of each leg seats in a mating socket76 of a temporary adjustable base 77 located beneath flange 71 in thelower portion 78 of a recess 79 formed in permanent base 27. Temporarybase 77 comprises a slidable member 80 carrying socket 76. Member 80 isslidably mounted in a guideway 81 on temporary fixed base member 82,defined by fixed side ribs 83 and adjustable shims 84 held in place bybolts 85, that properly laterally locates and guides member 80 formovement in the desired direction of movement of the lower end of theleg. Member 82 also has fixed end shoulders 86 and 87.

Member 82 is temporarily supported on three welded legs 91 that havethreaded into them adjusting bolts 92 hearing against metal bases 93resting on the bottom of recess 78, which has a suitably inclined andshaped bottom surface for the purpose. Bolts 92 and their bases 93permit the member 82, before it supports its associated leg 26, to bemounted in recess 78 with considerable accuracy as to a predeterminedlateral location, elevation and inclination.

During initial construction, the temporary base 77 for each leg isinstalled as accurately as possible utilizing the adjustability providedby the legs 91, bolts 92 and bases 93. Each base 77 is then mountedfirmly in place by concrete 94 (FIGS. 11, 13). After hardening of thisconcrete, each member 80 is then installed, being accurately located inits lateral position by insertion of proper shims 84; shims 88 are theninstalled adjacent shoulders 86 to limit properly the lateral outwardmovement of the lower ends of legs 26. The legs 26 and the remainder ofsupporting structure 9 are then erected; at this time the ball portion74 of each leg is seated in socket depression 76 of its member 80, theflange 71 being installed so the previously fixed anchor bolts extendthrough its slots 72. The offcenter distance Z, identical for each leg,has been calculated so that the weight of the supporting structure 9 inthe offcenter position of the ball portion tends to cause the lower endof each leg to move outwardly in guided movement of slidable member 80in fixed member 82. Such movement is assisted if necessary by forcing amovable wedge 95 into the space between slidable member 80 andstationary wedge 96 adjacent shoulder 87 of base 82. The temporarysupport of the legs on the ball and socket joints permits the lower endsof the legs to tilt or swivel as necessary.

After the lower portions of the legs have all been moved to the desiredprestressing position indicated in broken lines in FIG. 13, nuts 97 arepartially tightened on anchor bolts 73 to hold the legs in properposition. The space under the flange 71 is then completely filled inwith concrete grouting material 98 shown by broken lines; after thismaterial has hardened, the nuts 97 are fully tightened to lock the lowerends of the legs 26 in desired displaced position. The legs are thuslargely and if desired completely supported by the flanges 71. After thesupporting structure 9 is fully loaded, there is no prestress remainingin the legs 26, and no shear or bending moment at the lower portions ofthe legs.

If desired, before or after installing the furnace shell, the legs canbe filled either fully or for a major portion of their lengths withconcrete, preferably of a type that does not shrink, to stiffen thelegs. Holes 99 (FIG. 2) may be used for this purpose.

In the illustrated application the parts are so designed that the ballportions 74 and slidable members at the lower ends of the legs move ininclined paths essentially normal to the axes X of the legs duringprestressing; this is made possible by the inclined position of theguideways 81. The flanges 71 are also essentially normal to the axis ofthe legs. Such inclined movements and inclined relationships of theflanges are preferable, since they provide less bending moments in thelegs during prestressing than if the members 80 and ball portions 74moved in horizontal paths, and since the positions of the flanges 71normal to the axes X essentially eliminate shear and bending moments inthe legs after the legs are largely or fully supported by flanges 71.Lateral forces could be present if the flanges were not normal to axesX.

The concrete in the legs, after it has hardened and cured, stiffens thelegs 26 and acts to maintain them in their undeflected conditions, inwhich they have their maximum strength. This is particularly importantsince the frame structure as initially designed has deep, stiffcrossbeams 32, while the legs 26, while strong enough to support theload of the furnace even before the addition of the concrete, arerelatively limber since they are made of steel and capable of beingdeflected in the prestressing operation. The addition and curing ofconcrete while the legs are in their straight or undeflected positionsincreases the stiffness of the legs and their resistance toward bending.

The concrete in the legs also adds substantial mass to the large legs.This large added mass and the resistance of the concrete to compressiveforces provides added protection against damage from impacts on thelegs, thus adding to the safety of the structure. The mass of theconcrete also acts to substantially absorb and dissipate the energy ofeither steady or transient otherwise harmful vibrations to which thelegs or the furnace structure as a whole could be subjected. Concretethus set in each leg can also act as a highcapacity heat sink that canabsorb and transmit away from a point of localized exposure on the legheat from hot metal, slag or coke that might approach or contact thelegs.

While four legs of circular cross section are shown, one at each cornerof a four-sided supporting frame, supporting frames of different shapes,preferably polygonal, supported by a different number of legs may beused, and the legs may be of cross sections other than circular, such aspolygonal cross sections. In any event, the number and cross section ofthe legs should be such that adequate support and stability areprovided. It appears that for most, if not all, uses four legs and asquare-sided supporting frame are most advantageous from the standpointsof stability, adequate support, economy and cost. While the illustratedlegs are diagonally inclined for increased stability of the furnacestructure, they may be vertically disposed, if desired.

According to the present invention, an upright vessel may be adequatelyand safely supported by a strong, stable supporting structure in whichstresses are efficiently distributed. Studies have indicated that evenif one of the legs of the illustrated embodiment should be damaged oreliminated, the three remaining legs can safely support the entirestructure. Furthermore, studies also indicate that even if one of theillustrated eight sets of connecting members should be damaged or nun.na-m destroyed, the vessel would still remain safely supported in anupright position. These studies indicated that the redistribution ofloads can result in stresses greater than normal, but still within safemargins. The use of the described stabilizing ties was found to beparticularly helpful in maintaining steady support of the vessel undersuch conditions.

Other modifications will be apparent to those skilled in the art. It isintended that the patent shall cover, by suitable expression in theappended claims, whatever features of patentable novelty reside in theinvention.

What is claimed is:

1. Apparatus comprising a vessel having a shell capable of appreciableexpansion and contraction during normal operation of the apparatus, asupporting frame disposed about and spaced from said shell, ring meanssubstantially surrounding and secured to the shell adjacent said frame,and members connecting said frame and said ring means so that at alltimes during normal operation of the apparatus essentially all stress insaid connecting members is longitudinal stress, and during the expansionand contraction of the shell the magnitude of the longitudinal stress insaid connecting members and the magnitude of the stress in said ringmeans may fluctuate but without decreasing to zero stress and undergoingreversal of direction of stress in said connecting members and ringmeans.

2. The apparatus of claim 1 wherein said connecting members are alwaysin tension.

3. The apparatus of claim 1 wherein said connecting members areconnnected to said frame and to said ring means to support said shellfrom said frame and are always in tension.

4. The apparatus of claim 1 wherein said connecting members aresubstantially rigid.

5. The apparatus of claim 1 wherein said connecting members aresubstantially diagonally disposed with respect to the vertical.

6. The apparatus of claim 1 wherein said connecting members providesubstantially the only supporting connections between said frame andsaid ring means.

7. The apparatus of claim 1 wherein said shell is upright andsubstantially circular in horizontal cross section, and said connectingmembers extend substantially radially of the shell and are essentiallyequiangularly spaced around said shell.

8. The apparatus of claim 1 wherein said connecting members support saidshell from said frame at locations on said frame of essentially equaldeflection.

9. The apparatus of claim 1 wherein said supporting frame issubstantially square and carries a plurality of said connecting membersessentially radially disposed with respect to said shell, and saidconnecting members under longitudinal stress are secured to said frameat one end of each of said members.

10. The apparatus of claim 1 wherein said connecting members are securedto said ring means through gussets.

11. The apparatus of claim 10 wherein a plurality of said gussets aresubstantially radially disposed with respect to said shell, andreinforcing members rigidly connect adjacent ones of said gussets.

12. The apparatus of claim 10 wherein said shell is lined withrefractory material, and companion gussets are fixed to the inside ofsaid shell in said refractory material substantially in alignment withsaid first-mentioned gussets.

13. The apparatus of claim 12 wherein said companion gussets haveopenings therethrough that inhibit overstressing of said companiongussets.

14. Apparatus comprising a shell; support means for said shell includinga frame surrounding and spaced from the shell; and a plurality ofstabilizing means connectedbetween said frame and said shell, eachstabilizing means comprising tie members each of which is connected atone end to said shell and adjacent its other end to said frame, tiemembers of each stabilizing means crossing tie members of adjacentstabilizing means.

15. The apparatus of claim 14 wherein said tie members are pivotallysecured to said shell and said frame.

16. The apparatus of claim 14 including means for varying the length ofa tie member while it is connected to said frame and said fasteningmeans.

17. The apparatus of claim 14 wherein said frame is of polygonalconfiguration and surrounds said shell.

18. The apparatus of claim 14 comprising an auxiliary frame of polygonalconfiguration that surrounds said shell and is supported by saidfirst-mentioned frame, and wherein said tie members are pivotallysecured to said auxiliary frame adjacent the internal angles of thepolygon.

19. The apparatus of claim 14 wherein each stabilizing means comprises apair of tie members that extend oppositely from each other generallytangentially of said shell; and oppositely extending tie members ofadjacent stabilizing means cross.

20. The apparatus of claim 14 wherein said stabilizing means are atsubstantially the same elevation around the shell and are present insufficient number and spaced so that adjacent tie members of twocontiguous stabilizing means cross one another, one crossing tie membercomprising spacedapart strips and the other crossing tie membercomprising a strip passing between said spaced-apart strips.

21. Apparatus comprising a shell; a frame surrounding and spaced fromsaid shell, said frame comprising a plurality of beam members connectedto form a rigid polygonal structure having essentially equal sides andessentially equal internal angles, means for supporting said frame atsaid corners of said polygonal structure; means for supporting saidshell from said frame from locations on said beams of essentially equaldeflection, said means comprising supporting connecting membersextending between said locations of equal deflection on said beams andsaid shell; and stabilizing means comprising tie members connected tosaid shell and to said frame substantially at locations of equaldeflection on said beams.

22. The apparatus of claim 21 in which said shell is generally circularin cross section in a plane in which said tie members are substantiallyincluded, and in which said tie members are disposed generallytangentially to said shell.

23. The apparatus of claim 22 in which said stabilizing means areequiangularly disposed around said shell and include tie members thatcross tie members of adjacent tie means.

24. The apparatus of claim 21 comprising ring means that is fixed tosaid beam members of said frame, to which ring means said tie membersare connected.

25. The apparatus of claim 24 in which said ring means comprises apolygonal ring member having essentially equal sides and at its internalcorners essentially equal angles, and in which said tie members areconnected to said ring member substantially at its corners.

26. The apparatus of claim 25 in which said corners of said polygonalring member are located substantially at locations of equal deflectionon the beam members of said frame member.

27. The apparatus of claim 21 in which at each of said locations ofequal deflection on said beams the tie members extend generallytangentially toward and are connected to said shell, and in which thetie members are so connected to different beam members of said polygonalframe and tangentially connected to said shell that the tie members arearranged in sets that define separate polygons displaced angularlyaround the shell and no adjacent connecting means are located at tiemembers of the same polygon.

28. The apparatus of claim 27 in which separate polygons defined by saidtie members are a plurality of squares.

29. The apparatus of claim 27 in which said separate polygons defined bysaid generally horizontal members are squares.

30. Apparatus comprising a vessel having a shell capable of appreciabledimensional change during operation of the apparatus; supportingstructure comprising a frame surrounding and spaced from said shell,said frame comprising a plurality of beam members connected to form arigid polygonal structure having essentially equal sides and essentiallyequal internal angles, and legs rigidly connected to frame at saidcorners of said polygonal structure for supporting said frame; means forsupporting said vessel from said frame from locations on said beams ofessentially equal deflection, said means comprising supportingconnecting members extending between said locations of equal deflectionon said beams and said shell; stabilizing means comprising tie membersconnected to said shell and to said frame substantially at saidlocations of equal deflection on said beams; and means for prestressingsaid legs during construction of said supporting structure before it isloaded with said vessel by moving the lower end of each leg in adirection and by an amount essentially corresponding to the directionand amount said lower end of said leg would be moved when saidsupporting structure is subjected to a load corresponding to said shell,comprising means for temporarily supporting each of said legs duringconstruction and before loading of the vessel at a location that isdisplaced from the centerline of said leg in a direction opposite to thedirection in which the lower end of said leg would so move during suchprestressing.

31. The apparatus of claim 1 wherein said connecting members arearranged in a plurality of sets around said shell and each of said setscomprises a plurality of connecting members.

32. The apparatus of claim 1 wherein said shell is generally circular incross section, said frame is made up of beam members defining a polygon,and said connecting members are arranged in a plurality of sets toextend radially of said shell and be supported by said beam members atlocations thereon of equal deflection, each of said sets comprising aplurality of said connecting members.

34. The apparatus of claim 1 wherein each of said sets of connectingmembers comprises two pairs of connecting members, the connectingmembers of each pair being affixed to opposite sides of a gusset fixedto said frame and ofa gusset fixed to said shell.

33. T The apparatus of claim 32 wherein two sets of connecting membersare attached to each of said beam members at locations spaced along saidbeam members.

35. Apparatus comprising a vessel having a shell, an essentially rigidsupporting frame disposed about and spaced from said shell, and membersconnecting said frame and said shell so that during normal operation ofsaid apparatus essentially all stress in said connecting members is atall times longitu dinal tension stress and while the magnitude of saidlongitudinal stress in said connecting members may fluctuate said stressin said connecting members does not decrease to zero stress and undergoreversal of direction.

36. The apparatus of claim 35 wherein said connecting members arearranged in a plurality of sets around said shell and each of said setscomprises a plurality of connecting members.

37. The apparatus of claim 35 wherein each of said sets of connectingmembers comprises two pairs of identical connecting members, theconnecting members of each pair being affixed to opposite sides of agusset fixed to said frame and a gusset fixed to said shell.

38. The apparatus of claim 35 wherein two sets, each of a plurality ofconnecting members, are attached to each of said beam members atlocations spaced along said beam members.

39. Apparatus comprising a shell; a frame surrounding and spaced fromsaid shell, said frame comprising a plurality of beam members connectedto form a rigid polygonal structure; means for supporting said polygonalstructure; ring means fixed to said beam members of said frame toprevent tilting of said beam members about axes extending longitudinallyof said beam members; connecting means extending generally radially ofsaid shell for supporting said shell from said frame; and tensionmembers connected to said shell and said frame members; each of saidbeam members having connected to it essentially at a common locationalong the beam member said rin member, a connectin means, and a tensionmember.

0. The apparatus of c am 39 in which the beam members comprising saidrigid polygonal frame are of essentially equal lengths; in which saidmeans for supporting said frame supports it from the corners of saidpolygonal structure; in which said connecting members are connected tosaid beams at locations thereon of equal deflection; in which said ringmeans is connected to said beams defining said polygonal structure atsaid locations of equal deflection; and in which said tension membersare connected to said beam at said locations of equal deflection.

41. The apparatus of claim 39 in which said means for supporting saidframe supports it at the corners of said polygonal structure; in whichsaid connecting members are connected to each beam at a plurality oflocations thereon of equal deflection thereon; in which said ring meansis connected to each of said members at said locations of equaldeflection; and in which at each of said locations of equal defleCtionsaid tension members are connected to the beam members.

42. Apparatus comprising a shell; a frame surrounding and spaced fromsaid shell, said frame comprising a plurality of generally horizontalbeam members connected to form a rigid polygonal structure; means forsupporting said polygonal structure; ring means fixed to said beammembers of said frame to prevent tilting of said beam members about axesextending longitudinally of said beam members; a plurality of connectingmeans spaced around the shell and extending generally radially of saidshell and connected to the beam members of said frame and to said shellfor supporting said shell from said frame so that during normaloperation of the apparatus the forces in said connecting members are atall times longitudinal tension forces; and generally horizontal membersconnected to said shell and said frame members; said ring means,connecting means and said generally horizontal members being so arrangedthat at locations on the beam members at which a connecting means isconnected, the action lines of the forces in said connecting means, inthe ring means, and in a plurality of tension members substantiallyintersect.

43. The apparatus of claim 42 in which the beam members comprising saidrigid polygonal frame are of essentially equal lengths; in which saidmeans for supporting said frame supports it from the corners of saidpolygonal structure; in which said connecting means are connected tosaid members at locations thereon of equal deflection; in which saidring means is connected to said beam members at said locations of equaldeflection; and in which pairs of diverging tension members areconnected to said beam members at said locations of equal deflection.

44. The apparatus of claim 42 in which said means for supporting saidframe supports it at the corners of said polygonal structure; in whichsaid connecting members are connected to each beam at a plurality oflocations thereon of equal deflection thereon; in which said ring meansis connected to each of said members at said locations of equaldeflection; and in which at each of said location of equal deflectionsaid tension members are connected to the beam member.

45. Apparatus comprising a shell; a generally horizontal framesurrounding and spaced from said shell, said frame comprising aplurality of beam members connected to form a rigid structure; means forsupporting said frame; a plurality of connecting means spaced aroundsaid shell and extending between said frame and said shell andsupporting said shell from said beam members of said frame; andgenerally horizontal members connected to said shell and said beamssubstantially at the locations on said beams at which said connectingmeans are located said generally horizontal members being arranged insets that define separate polygons displaced angularly around said shellso that no adjacent connecting means are located at tie members of thesame polygon.

1. Apparatus comprising a vessel having a shell capable of appreciableexpansion and contraction during normal operation of the apparatus, asupporting frame disposed about and spaced from said shell, ring meanssubstantially surrounding and secured to the shell adjacent said frame,and members connecting said frame And said ring means so that at alltimes during normal operation of the apparatus essentially all stress insaid connecting members is longitudinal stress, and during the expansionand contraction of the shell the magnitude of the longitudinal stress insaid connecting members and the magnitude of the stress in said ringmeans may fluctuate but without decreasing to zero stress and undergoingreversal of direction of stress in said connecting members and ringmeans.
 2. The apparatus of claim 1 wherein said connecting members arealways in tension.
 3. The apparatus of claim 1 wherein said connectingmembers are connnected to said frame and to said ring means to supportsaid shell from said frame and are always in tension.
 4. The apparatusof claim 1 wherein said connecting members are substantially rigid. 5.The apparatus of claim 1 wherein said connecting members aresubstantially diagonally disposed with respect to the vertical.
 6. Theapparatus of claim 1 wherein said connecting members providesubstantially the only supporting connections between said frame andsaid ring means.
 7. The apparatus of claim 1 wherein said shell isupright and substantially circular in horizontal cross section, and saidconnecting members extend substantially radially of the shell and areessentially equiangularly spaced around said shell.
 8. The apparatus ofclaim 1 wherein said connecting members support said shell from saidframe at locations on said frame of essentially equal deflection.
 9. Theapparatus of claim 1 wherein said supporting frame is substantiallysquare and carries a plurality of said connecting members essentiallyradially disposed with respect to said shell, and said connectingmembers under longitudinal stress are secured to said frame at one endof each of said members.
 10. The apparatus of claim 1 wherein saidconnecting members are secured to said ring means through gussets. 11.The apparatus of claim 10 wherein a plurality of said gussets aresubstantially radially disposed with respect to said shell, andreinforcing members rigidly connect adjacent ones of said gussets. 12.The apparatus of claim 10 wherein said shell is lined with refractorymaterial, and companion gussets are fixed to the inside of said shell insaid refractory material substantially in alignment with saidfirst-mentioned gussets.
 13. The apparatus of claim 12 wherein saidcompanion gussets have openings therethrough that inhibit overstressingof said companion gussets.
 14. Apparatus comprising a shell; supportmeans for said shell including a frame surrounding and spaced from theshell; and a plurality of stabilizing means connected between said frameand said shell, each stabilizing means comprising tie members each ofwhich is connected at one end to said shell and adjacent its other endto said frame, tie members of each stabilizing means crossing tiemembers of adjacent stabilizing means.
 15. The apparatus of claim 14wherein said tie members are pivotally secured to said shell and saidframe.
 16. The apparatus of claim 14 including means for varying thelength of a tie member while it is connected to said frame and saidfastening means.
 17. The apparatus of claim 14 wherein said frame is ofpolygonal configuration and surrounds said shell.
 18. The apparatus ofclaim 14 comprising an auxiliary frame of polygonal configuration thatsurrounds said shell and is supported by said first-mentioned frame, andwherein said tie members are pivotally secured to said auxiliary frameadjacent the internal angles of the polygon.
 19. The apparatus of claim14 wherein each stabilizing means comprises a pair of tie members thatextend oppositely from each other generally tangentially of said shell;and oppositely extending tie members of adjacent stabilizing meanscross.
 20. The apparatus of claim 14 wherein said stabilizing means areat substantially the same elevation around the shell and are present insufficient number and spaced so that adjacent tiE members of twocontiguous stabilizing means cross one another, one crossing tie membercomprising spaced-apart strips and the other crossing tie membercomprising a strip passing between said spaced-apart strips. 21.Apparatus comprising a shell; a frame surrounding and spaced from saidshell, said frame comprising a plurality of beam members connected toform a rigid polygonal structure having essentially equal sides andessentially equal internal angles, means for supporting said frame atsaid corners of said polygonal structure; means for supporting saidshell from said frame from locations on said beams of essentially equaldeflection, said means comprising supporting connecting membersextending between said locations of equal deflection on said beams andsaid shell; and stabilizing means comprising tie members connected tosaid shell and to said frame substantially at locations of equaldeflection on said beams.
 22. The apparatus of claim 21 in which saidshell is generally circular in cross section in a plane in which saidtie members are substantially included, and in which said tie membersare disposed generally tangentially to said shell.
 23. The apparatus ofclaim 22 in which said stabilizing means are equiangularly disposedaround said shell and include tie members that cross tie members ofadjacent tie means.
 24. The apparatus of claim 21 comprising ring meansthat is fixed to said beam members of said frame, to which ring meanssaid tie members are connected.
 25. The apparatus of claim 24 in whichsaid ring means comprises a polygonal ring member having essentiallyequal sides and at its internal corners essentially equal angles, and inwhich said tie members are connected to said ring member substantiallyat its corners.
 26. The apparatus of claim 25 in which said corners ofsaid polygonal ring member are located substantially at locations ofequal deflection on the beam members of said frame member.
 27. Theapparatus of claim 21 in which at each of said locations of equaldeflection on said beams the tie members extend generally tangentiallytoward and are connected to said shell, and in which the tie members areso connected to different beam members of said polygonal frame andtangentially connected to said shell that the tie members are arrangedin sets that define separate polygons displaced angularly around theshell and no adjacent connecting means are located at tie members of thesame polygon.
 28. The apparatus of claim 27 in which separate polygonsdefined by said tie members are a plurality of squares.
 29. Theapparatus of claim 27 in which said separate polygons defined by saidgenerally horizontal members are squares.
 30. Apparatus comprising avessel having a shell capable of appreciable dimensional change duringoperation of the apparatus; supporting structure comprising a framesurrounding and spaced from said shell, said frame comprising aplurality of beam members connected to form a rigid polygonal structurehaving essentially equal sides and essentially equal internal angles,and legs rigidly connected to frame at said corners of said polygonalstructure for supporting said frame; means for supporting said vesselfrom said frame from locations on said beams of essentially equaldeflection, said means comprising supporting connecting membersextending between said locations of equal deflection on said beams andsaid shell; stabilizing means comprising tie members connected to saidshell and to said frame substantially at said locations of equaldeflection on said beams; and means for prestressing said legs duringconstruction of said supporting structure before it is loaded with saidvessel by moving the lower end of each leg in a direction and by anamount essentially corresponding to the direction and amount said lowerend of said leg would be moved when said supporting structure issubjected to a load corresponding to said shell, comprising means fortemporarily supporting each of said legs during construction and beforeloading of the vessel at a location that is displaced from thecenterline of said leg in a direction opposite to the direction in whichthe lower end of said leg would so move during such prestressing. 31.The apparatus of claim 1 wherein said connecting members are arranged ina plurality of sets around said shell and each of said sets comprises aplurality of connecting members.
 32. The apparatus of claim 1 whereinsaid shell is generally circular in cross section, said frame is made upof beam members defining a polygon, and said connecting members arearranged in a plurality of sets to extend radially of said shell and besupported by said beam members at locations thereon of equal deflection,each of said sets comprising a plurality of said connecting members. 33.The apparatus of claim 32 wherein two sets of connecting members areattached to each of said beam members at locations spaced along saidbeam members.
 34. The apparatus of claim 1 wherein each of said sets ofconnecting members comprises two pairs of connecting members, theconnecting members of each pair being affixed to opposite sides of agusset fixed to said frame and of a gusset fixed to said shell. 35.Apparatus comprising a vessel having a shell, an essentially rigidsupporting frame disposed about and spaced from said shell, and membersconnecting said frame and said shell so that during normal operation ofsaid apparatus essentially all stress in said connecting members is atall times longitudinal tension stress and while the magnitude of saidlongitudinal stress in said connecting members may fluctuate said stressin said connecting members does not decrease to zero stress and undergoreversal of direction.
 36. The apparatus of claim 35 wherein saidconnecting members are arranged in a plurality of sets around said shelland each of said sets comprises a plurality of connecting members. 37.The apparatus of claim 35 wherein each of said sets of connectingmembers comprises two pairs of identical connecting members, theconnecting members of each pair being affixed to opposite sides of agusset fixed to said frame and a gusset fixed to said shell.
 38. Theapparatus of claim 35 wherein two sets, each of a plurality ofconnecting members, are attached to each of said beam members atlocations spaced along said beam members.
 39. Apparatus comprising ashell; a frame surrounding and spaced from said shell, said framecomprising a plurality of beam members connected to form a rigidpolygonal structure; means for supporting said polygonal structure; ringmeans fixed to said beam members of said frame to prevent tilting ofsaid beam members about axes extending longitudinally of said beammembers; connecting means extending generally radially of said shell forsupporting said shell from said frame; and tension members connected tosaid shell and said frame members; each of said beam members havingconnected to it essentially at a common location along the beam membersaid ring member, a connecting means, and a tension member.
 40. Theapparatus of claim 39 in which the beam members comprising said rigidpolygonal frame are of essentially equal lengths; in which said meansfor supporting said frame supports it from the corners of said polygonalstructure; in which said connecting members are connected to said beamsat locations thereon of equal deflection; in which said ring means isconnected to said beams defining said polygonal structure at saidlocations of equal deflection; and in which said tension members areconnected to said beam at said locations of equal deflection.
 41. Theapparatus of claim 39 in which said means for supporting said framesupports it at the corners of said polygonal structure; in which saidconnecting members are connected to each beam at a plurality oflocations thereon of equal deflection thereon; in which said ring meansis connected to each of said members at said locations of equaldeflection; and in which at each of said locations oF equal defleCtionsaid tension members are connected to the beam members.
 42. Apparatuscomprising a shell; a frame surrounding and spaced from said shell, saidframe comprising a plurality of generally horizontal beam membersconnected to form a rigid polygonal structure; means for supporting saidpolygonal structure; ring means fixed to said beam members of said frameto prevent tilting of said beam members about axes extendinglongitudinally of said beam members; a plurality of connecting meansspaced around the shell and extending generally radially of said shelland connected to the beam members of said frame and to said shell forsupporting said shell from said frame so that during normal operation ofthe apparatus the forces in said connecting members are at all timeslongitudinal tension forces; and generally horizontal members connectedto said shell and said frame members; said ring means, connecting meansand said generally horizontal members being so arranged that atlocations on the beam members at which a connecting means is connected,the action lines of the forces in said connecting means, in the ringmeans, and in a plurality of tension members substantially intersect.43. The apparatus of claim 42 in which the beam members comprising saidrigid polygonal frame are of essentially equal lengths; in which saidmeans for supporting said frame supports it from the corners of saidpolygonal structure; in which said connecting means are connected tosaid members at locations thereon of equal deflection; in which saidring means is connected to said beam members at said locations of equaldeflection; and in which pairs of diverging tension members areconnected to said beam members at said locations of equal deflection.44. The apparatus of claim 42 in which said means for supporting saidframe supports it at the corners of said polygonal structure; in whichsaid connecting members are connected to each beam at a plurality oflocations thereon of equal deflection thereon; in which said ring meansis connected to each of said members at said locations of equaldeflection; and in which at each of said locations of equal deflectionsaid tension members are connected to the beam member.
 45. Apparatuscomprising a shell; a generally horizontal frame surrounding and spacedfrom said shell, said frame comprising a plurality of beam membersconnected to form a rigid structure; means for supporting said frame; aplurality of connecting means spaced around said shell and extendingbetween said frame and said shell and supporting said shell from saidbeam members of said frame; and generally horizontal members connectedto said shell and said beams substantially at the locations on saidbeams at which said connecting means are located said generallyhorizontal members being arranged in sets that define separate polygonsdisplaced angularly around said shell so that no adjacent connectingmeans are located at tie members of the same polygon.